Hayward Gallery

Put your hand flat against the wall beside you. The concrete feels cool, rough and faintly ridged. Those fine lines are the grain of wooden boards. Builders poured wet concrete into timber moulds, and when the boards came away, the wood grain stayed behind in the stone. Look closely and you can follow single planks running across the surface. This is the Hayward Gallery, on London's South Bank, and almost every surface here carries a trace of the hands that made it.

The gallery opened in 1968. It sits within the Southbank Centre, the group of arts buildings stretched along the south side of the Thames. Its name honours Sir Isaac Hayward, a long-serving leader of the London County Council. That detail matters. The Hayward was not built by a private collector or a wealthy patron. It was built by local government, as part of a post-war belief that art, music and ideas should belong to everyone in the city.

The design came from architects working inside the Greater London Council. Several young members of that team, among them Ron Herron, Warren Chalk and Dennis Crompton, later became known as Archigram. Archigram was an experimental group of the 1960s. They imagined walking cities and plug-in buildings that you could swap out like parts of a machine. Here is the first surprise. The heavy, earthbound building in front of you was partly shaped by people who dreamed of architecture that could move.

The style is often called Brutalism. The word does not mean brutal. It comes from the French phrase "béton brut", which simply means raw concrete. Brutalist architects left their materials exposed and honest, with no paint and no decorative skin. For decades many Londoners disliked buildings like this one. Some called for them to be pulled down. Today, opinion has turned, and people travel from across the world to photograph exactly these grey, angular forms.

Now step back and look at the shape of the building. It does not present one grand front door. Instead it stacks up in blocks and platforms, with stairs, ramps and walkways running between them. The architects designed the South Bank as a series of raised decks, so people could walk above the traffic. Some of those walkways have since been changed or closed. Even so, you can still feel the original idea — a landscape of concrete that you explore, rather than a single building that you enter.

Look up at the roof if you can see it from where you stand. Rows of glass pyramids sit along the top of the upper galleries. They were designed to bring daylight down into the rooms below. For years, the light never quite worked as planned. During a major refurbishment that closed the gallery for over two years, the pyramids were rebuilt. When the Hayward reopened in 2018, for its fiftieth anniversary, natural light finally fell into those galleries the way its designers had hoped.

Here is the second surprise. The Hayward has no permanent collection on its walls. There is no famous painting waiting for you in the same room every year. Every exhibition is temporary. Each show takes over the building for a few months, then the rooms are emptied and rebuilt for something completely different. So the gallery you visit today may look and feel nothing like the gallery a friend visited last season.

That freedom has produced some memorable moments. In 2015, the artist Carsten Höller installed giant tube slides that carried visitors out of the building and down the outside walls. Earlier, the sculptor Antony Gormley filled the rooms with a glowing cloud of dense fog, and placed lifelike human figures on rooftops across this part of London. The Hayward has also hosted large shows built entirely from light. The concrete becomes a kind of stage, and each artist decides what play to perform.

The building also has a sculpture terrace, an open-air platform at upper level. Large works are sometimes shown out here, under the open sky. From the terrace you see a mix of old and new London — the river, the bridges, the towers on the opposite bank. The view changes with the weather. On a grey day, the concrete and the sky almost become one colour. On a bright afternoon, sharp shadows cut across every ledge and step.

Watch for the tower of coloured light on the roof. It is a kinetic sculpture from the early 1970s. Its lights respond to the wind, so the colours shift with the speed and direction of the air above the Thames. Many people walk past without noticing that it is reacting to the weather in real time. Stand still for a moment after dusk and you may see the pattern change as the breeze picks up.

The neighbours are part of the experience. Next door stand the Queen Elizabeth Hall and the Purcell Room, both concert spaces from the same era and the same family of concrete. A short walk west brings you to the Royal Festival Hall, built for the Festival of Britain in 1951. Beneath the walkways, skateboarders have used the covered undercroft for decades. You can often hear the clatter of wheels on concrete before you see them.

The sounds around you are worth a moment. Listen for the hollow echo of footsteps on the stairs, the rumble of trains crossing nearby bridges, and the gulls calling over the river. On weekends, the riverside path fills with street performers, food stalls and families walking along the water. Under Waterloo Bridge, booksellers lay out second-hand books on long tables. The Hayward sits at the centre of all this movement, solid and quiet.

Before you move on, look once more at the concrete beside you. Find a single board mark, and follow it with your eye until it stops. Someone measured that plank, cut it and fixed it in place more than half a century ago. The building is still here, still changing its contents every few months, still asking London what art can be. As you walk away along the river, notice how often that grey board-marked texture appears around you — and how it changes in the light.